On Thu, Jan 19, 2017 at 03:28:25PM -0500, Richard Heck wrote:
> On 01/19/2017 02:35 PM, Enrico Forestieri wrote:
> >
> > In conclusion, your patch textwidth2.diff is the right thing to do
> > in master. For stable we have to make a decision. The alternatives are:
> >
> > 1) The patch I posted earlier (textwidth.diff), amended to account
> > for single chars. This restores the previous behavior, where \not
> > only works properly with mathrel operators.
> >
> > 2) The not1.diff patch. This is essentially equivalent to 1) but avoids
> > the \kern in the definition of \not.
> >
> > 3) The not2.diff patch. This makes \ne, \neq, and \notin work again
> > and fixes the usage of \not with other non-mathrel characters,
> > while breaking it for \not=, \not\in and other mathrel operators.
> >
> > I would suggest to choose either 1) or 2), which simply restore the
> > previous behavior.
>
> Either of those would be fine with me.
As I don't see what we gain from 2), I think 1) is the way to go. I attach
here the amended patch.
--
Enrico
diff --git a/src/frontends/qt4/GuiFontMetrics.cpp b/src/frontends/qt4/GuiFontMetrics.cpp
index f17ac37..83b2a1f 100644
--- a/src/frontends/qt4/GuiFontMetrics.cpp
+++ b/src/frontends/qt4/GuiFontMetrics.cpp
@@ -178,16 +178,27 @@ int GuiFontMetrics::width(docstring const & s) const
int * pw = strwidth_cache_[s];
if (pw)
return *pw;
+#endif
// For some reason QMetrics::width returns a wrong value with Qt5
- // int w = metrics_.width(toqstr(s));
+ // with some arabic text. OTOH, QTextLayout is broken for single
+ // characters with null width (like \not in mathed). Also, as a
+ // safety measure, always use QMetrics::width with our math fonts.
+ int w = 0;
+ if (s.length() == 1
+#if QT_VERSION >= 0x040800
+ || font_.styleName() == "LyX"
#endif
- QTextLayout tl;
- tl.setText(toqstr(s));
- tl.setFont(font_);
- tl.beginLayout();
- QTextLine line = tl.createLine();
- tl.endLayout();
- int w = int(line.naturalTextWidth());
+ )
+ w = metrics_.width(toqstr(s));
+ else {
+ QTextLayout tl;
+ tl.setText(toqstr(s));
+ tl.setFont(font_);
+ tl.beginLayout();
+ QTextLine line = tl.createLine();
+ tl.endLayout();
+ w = int(line.naturalTextWidth());
+ }
#ifdef CACHE_METRICS_WIDTH
strwidth_cache_.insert(s, new int(w), s.size() * sizeof(char_type));
#endif
